Exam 4: The Structure and Function of the Plasma Membrane

While culturing some cells, you lower the temperature of the culture. What happens immediately to the membrane fluidity?

On average, how many amino acids, forming a hydrophobic $\alpha$ -helix, does it take to cross the hydrophobic part of the membrane?

You treat some cells with a proteolytic enzyme that is too large to penetrate the cell membrane (Set 1). Another group of cells is made permeable to the enzyme before treatment with the enzyme (Set 2). A third set of cells was not treated with the enzyme at all (controls). Proteins are then extracted from the three different sets of cells and applied to an SDS-PAGE gel. Protein W migrates to the same distance on a gel of proteins from Set 1 and Set 2; Protein W migrates a shorter distance on gels of proteins extracted from the control group than on gels of proteins extracted from Set 1 and Set 2 treated cells. Protein X migrates to the same distance on a gel of proteins from control cells and the gels of the proteins from Set 1 and Set 2. Protein Y migrates a longer distance when extracted from Set 1 cells than does protein Y in the controls; Protein Y moves an even larger distance in the gel of the extracts from Set 2. Protein Z migrates the same distance on gels of proteins from the controls and the proteins extracted from Set 1, but it migrates a longer distance in extracts from Set 2 cells. Which protein is exposed only on the exterior of the cell?

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

You treat some cells with a proteolytic enzyme that is too large to penetrate the cell membrane (Set 1). Another group of cells is made permeable to the enzyme before treatment with the enzyme (Set 2). A third set of cells was not treated with the enzyme at all (controls). Proteins are then extracted from the three different sets of cells and applied to an SDS-PAGE gel. Protein W migrates to the same distance on a gel of proteins from Set 1 and Set 2; Protein W migrates a shorter distance on gels of proteins extracted from the control group than on gels of proteins extracted from Set 1 and Set 2 treated cells. Protein X migrates to the same distance on a gel of proteins from control cells and the gels of the proteins from Set 1 and Set 2. Protein Y migrates a longer distance when extracted from Set 1 cells than does protein Y in the controls; Protein Y moves an even larger distance in the gel of the extracts from Set 2. Protein Z migrates the same distance on gels of proteins from the controls and the proteins extracted from Set 1, but it migrates a longer distance in extracts from Set 2 cells. Which protein is likely to have a cytosolic domain and be exposed only on the interior of the cell?

What factor(s)directly or indirectly determine the transition temperature? (Select all correct choices)

_________ is the movement of a substance from an area of high concentration to an area of lower concentration.

The movement of water through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration is called ________.

______influx triggers fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell. This same stimulus also triggers __________, releasing neurotransmitters.

To date, the most successful neurotechnology advances have occurred in _________________.

What are the building blocks of a phosphoglyceride, specifically phosphatidic acid?

In plants, the analogous mechanism to action potential propagation in animal neuron axons is _________________________.

Why might integral membrane proteins be difficult to study based upon what you know of their amino acid composition?

As an action potential is initiated, the membrane is __________. This is caused by the ________ of ________ ions.

Which property of membranes allows interactions like the assembly of membrane protein clusters at particular sites and the formation of specialized structures to take place within the membrane?

Which substance will cross a plasma membrane most effectively?

Impulse propagation by a myelinated axon is called ____________ conduction.

People who have the O blood type possess ________.

Which of the following is NOT a function of membranes?